Gamut-preserving color imaging
View Patent ↗A color imaging technique includes setting a target value in a device-independent first color space and mapping the target value to a substantially complete point set in a second color space. The point set may include a plurality of points, each of which define substantially the same colorimetric value via a unique combination of colorants. After mapping the target value to a substantially complete point set, a point may be chosen. Moreover, after choosing a point in the point set, device-dependent colorant values defined by the point may be determined. In this manner, the invention may provide control over the colorants that are used to image a particular color.
1. A method comprising:
setting a target value in a device-independent first color space,
mapping the target value to a point set in a second color space, wherein the point set defines a plurality of points each of which define a colorimetric value via a unique combination of colorants and wherein the colorimetric value defined by each point in the point set is substantially the same, and
choosing a point from the point set based, at least in part, on a spectrally-based comparison between a first spectrum associated with the target value and a set of spectra associated with points in the point set.
2. The method of claim 1 , wherein the second color space is a device-dependent color space.
3. The method of claim 1 , wherein the first color space is an n-dimensional color space, and the second color space is an m-dimensional color space, wherein m is greater than n.
4. The method of claim 1 , the method further comprising:
determining a set of device-dependent colorant values defined by the point in the point set.
5. The method of claim 4 , the method further comprising:
printing a color, the color being defined by the set of device-dependent colorant values.
6. The method of claim 1 , wherein the target value has a colorimetric value substantially equal to the colorimetric value of each of the points in the point set.
7. The method of claim 1 , wherein the first color space is a three-dimensional color space.
8. The method of claim 1 , wherein the second color space is a four-dimensional color space.
9. The method of claim 8 , wherein the point set is a space curve.
10. The method of claim 8 , wherein the second color space is defined by four colors: black, magenta, cyan, and yellow.
11. The method of claim 8 , wherein the second color space is defined by at least four colors of the following group of colors: black, magenta, cyan, yellow, orange and green.
12. The method of claim 1 , wherein choosing a point in the point set is manually performed by an end user.
13. The method of claim 1 , wherein choosing a point on the point set is automatically performed by a machine.
14. The method of claim 13 , wherein the machine monitors at least one variable, the variable defining at least one machine operational condition, and the machine chooses the point in the point set based, at least in part, on the variable.
15. A system comprising:
a memory that stores a target value, the target value being a value in a device-independent first color space; and
a processor that maps the target value to a point set in a second color space and chooses a point from the point set based, at least in part, on a spectrally-based comparison between a first spectrum associated with the target value and a set of spectra associated with points in the point set, wherein the point set defines a plurality of points each of which define a colorimetric value via a unique combination of colorants and wherein the colorimetric value defined by each point in the point set is substantially the same.
16. The system of claim 15 , wherein the second color space is a device-dependent color space.
17. The system of claim 15 , wherein the first color space is an n-dimensional color space, and the second color space is an m-dimensional color space,
wherein in is greater than n.
18. The system of claim 15 , wherein the processor determines a set of device-dependent colorant values defined by the point in the point set.
19. The system of claim 18 , further comprising a printer that prints a color, the color being defined by the set of device-dependent colorant values.
20. The system of claim 15 , wherein the target value has a colorimetric value substantially equal to the colorimetric value of all points in the point set.
21. The system of claim 15 , wherein the processor monitors at least one variable, the variable defining at least one printer condition; and
wherein the processor chooses the point in the point set as determined, at least in part, by the variable.
22. A method comprising:
setting a target value in a device-independent first color space,
mapping the target value to a space curve in a second color space,
representing the space curve as a collection of parametric curves, and
choosing a point on the space curve, wherein choosing the point on the space curve is automatically performed by a machine, and wherein the machine chooses the point on the space curve based, at least in part. on a spectrally-based comparison between a first spectrum associated with the target value and a set of spectra associated with points on the space curve.
23. The method of claim 22 , wherein the second color space is a device-dependent color space.
24. The method of claim 22 , wherein the first color space is an n-dimensional color space, and the second color space is an m-dimensional color space,
wherein m is greater than n.
25. The method of claim 22 , the method further comprising:
determining a set of device-dependent colorant values defined by the point on the space curve.
26. The method of claim 25 , the method further comprising:
printing a color, the color being defined by the set of device-dependent colorant values.
27. The method of claim 22 , wherein the target value has a colorimetric value substantially equal to the colorimetric value of all points on the space curve.
28. The method of claim 22 , wherein the first color space is a three-dimensional color space.
29. The method of claim 22 , wherein the second color space is a four-dimensional color space.
30. The method of claim 29 , wherein the second color space is defined by four colors: black, magenta, cyan, and yellow.
31. The method of claim 29 , wherein the second color space is defined by four colors of the following group of colors: black, magenta, cyan, yellow, orange and green.
32. The method of claim 22 , wherein the machine monitors at least one variable, the variable defining at least one machine operational condition;
and wherein the machine chooses a point on the space curve as determined, at least in part, by the variable.
33. A computer-readable medium containing program code that when executed by a computer:
sets a target value in a device-independent first color space,
maps the target value to a point set in a second color space, wherein the point set defines a plurality of points each of which define a colorimetric value via a unique combination of colorants and wherein the colorimetric value defined by each point in the point set is substantially the same, and
chooses a point from the point set based, at least in part, on a spectrally-based comparison between a first spectrum associated with the target value and a set of spectra associated with points in the point set.
34. A method comprising:
setting a target value in a device-independent first color space,
mapping the target value to a substantially complete point set in a second color space, wherein the point set defines a plurality of points each of which define a colorimetric value via a unique combination of colorants and wherein the colorimetric value defined by each point in the point set is substantially the same, and
choosing a point from the point set based, at least in part, on a variable defining at least one machine operational condition.
35. The method of claim 34 , wherein the machine operational condition comprises a level of one or more colorants currently in a printer.
36. A method comprising:
setting a target value in a device-independent first color space,
mapping the target value to a substantially complete point set in a second color space, wherein the point set defines a plurality of points each of which define a colorimetric value via a unique combination of colorants and wherein the colorimetric value defined by each point in the point set is substantially the same, and
choosing a point from the point set based, at least in part, on a spectrally-based comparison between a first spectrum associated with the target value and a set of spectra associated with points in the point set.
37. A method comprising:
setting a target value in a device-independent first color space,
mapping the target value to a space curve in a second color space,
representing the space curve as a collection of parametric curves, and
choosing a point on the space curve, wherein choosing the point on the space curve is manually performed by an end user.